CheckStakeKernelHash help needed (btcd port)

Protocol
1

Hi everybody,

I am working on the btcd port for peercoin.

Blockchain sync is stuck on block 7661 because the corresponding proof of stake hash is not considered valid.

All previous PoS blocks are passing all validation steps perfectly fine, so we are probably on some edge case.

I would like to verify that I am correctly building the corresponding array of bytes to be hashed to exclude that possibility.

Here are the values used for building the byte array (check code links below):

nBits=470557660
nTimeBlockFrom=1345496436
nTxPrevOffset=195
txPrev.nTime=1345496397
prevout.n=1
nTimeTx=1348905506

Here is what I obtain after concatenating the values above:
[220 35 12 28 116 165 50 80 195 0 0 0 77 165 50 80 1 0 0 0 34 170 102 80] (decimal form)
[DC 23 0C 1C 74 A5 32 50 C3 00 00 00 4D A5 32 50 01 00 00 00 22 AA 66 50] (hexa form)

Which gives me after double sha256 hashing:
849055dc415056668ce1678f7e3472e16bddd4f29d240c84329d0adabfab7096 (invalid)

Instead of:
00000208ca3c0d2a2ee562b10e5b3b89630fe0eb03b2311fedb9b411af751883 (correct)

Two possibilities: either the values used for calculating the hash are erroneous, either the Go hash method has a bug.
I would prefer the first possibility :slight_smile: Can someone verifiy that these are the right values for block #7661 ?

Any help will be really greatly appreciated.

Thanx in advance.

Original peercoin core code: https://github.com/ppcoin/ppcoin/blob/master/src/kernel.cpp#L313
Our ppcd code: https://github.com/mably/btcchain/blob/mably/kernel.go#L406

2

For the developers out there, you can reproduce the error by running the following command in the btcchain project folder:

[tt]go test -v ppc_processblock_test.go[/tt]

You also have to copy the blk0001.dat blockchain file from peercoin core to the testdata subfolder before running the test.

This test will try to import in ppcd the 10000 first blocks of the peercoin blockchain.

As said in OP, this test will fail for block of height 7661 :frowning:

3

Ok, sorry guys, the error was on my side. I was using erroneous previous transaction info to build the proof of stake hash.

Everything is running fine up to block height 10000. Will try to finalize blockchain sync now.